If I'm you, I'd stay FAR FAR FAR away from weight/mass gainer.

Its too expensive and not worth your time in KL. It is "cheaper" than whey but that's because 50% is sugar and dextrose - rubbish carbs to increase cals.

The only way it would be worth is if you have a super-fast metabolism or a pro-athlete training schedule and need huge amounts of calories.

Just buy whey and go eat nasi lemak special later - cheaper and whole food provide a better boost. Or alternatively go buy a huge bag of white sugar and mix few scoops with your whey shake - it comes out the same macro wise plus Govt subsidised your shake too. 

If this is your advice, I'll say that you know nothing about how body works. Do you think that mass gainers is a magic powder that help you grow big?

It makes sense...........
If you're in prison.

What if I tell you that even by following the mass gainers' recommended serving, you MAY not be able to increase your weight.

I'm just want to argue with him about this:
How can even he recommend someone to take that kind of serving without even knowing how much calorie the person should take. For me, I'm reliable for every tips/trick/advices I give to other people.